Add Reblogging and Announce support for ActivityPub

[akirk]

This adds a button "Reblog" to each item. Depending on the setting (see below), it will post the same post under your own name on your blog, and if the post is on ActivityPub, it will announce = boost it there.

ActivityPub Settings

This adds a new ActivityPub settings page that allows to disable the automatic creation of a reblog post:

Different buttons

If it is a post that came in via ActivityPub, then it can be either this

or this, depending on the setting above.

If it is a plain blog post, you get a reblog button:

Reblogged/boosted posts will be annotated with a checkmark:

Fixes #186.

[akirk]

@pfefferle could you advise how I could best have these reblog posts appear as Announce in the outbox, can I just propose to add a filter to this for loop?

[pfefferle]

Hey @akirk yes you could but it would make pagination really hard. As far as I know, the outbox is not (yet) really used by other platforms and I have some ideas to optimize the code. Maybe you skip the step and we chat about a more flexible inbox/outbox feature. Just as a quick sum up: there is a problem of different db objects that should all be in the outbox, like comments, posts, custom post types, ... that makes it impossible to generate the info on the fly (like I am currently doing with only posts). My idea is to build a custom post type for activities, that only reference the local WordPress object (maybe using taxonomies for inbox/outbox). So every activity on WordPress will generate an Outbox Activity and the push mechanism (cron) will also use this construct for publishing. To publish an activity in the future, you simply have to create such an custom post type activity and the rest is done by the plugin. I hope you got my point and I am curious about your feedback!

[akirk]

@pfefferle, pagination is not my concern since the reblog'ed post would be 1:1 replaced with an announce activity.

Let's have a chat indeed about your ideas, a custom post type would certainly work, it'd just double the amount of data and has potential for inconsistencies (like when a plugin creates/updates/deletes a new post/comment without using the WordPress functions).

[akirk]

Re outbox, I am using it in #163 for backfilling posts.